Diaphragm Muffler and Method of Use

ABSTRACT

A diaphragm muffler for quiet operation of a compressor imparting an above atmospheric pressure stream and a below atmospheric pressure stream. The diaphragm muffler including a diaphragm pressure chamber receiving the above atmospheric pressure stream; a diaphragm vacuum chamber receiving the below atmospheric pressure stream; and a flexible diaphragm dividing the diaphragm pressure chamber receiving the above atmospheric pressure stream from the diaphragm vacuum chamber receiving the below atmospheric pressure stream, whereby the above atmospheric pressure stream and the below atmospheric pressure stream cancel each other out via the flexible diaphragm.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims the benefit of U.S. Provisional Patent Application 60/933,675 filed Jun. 8, 2007 under 35 U.S.C. 119(e). This application is incorporated by reference herein as though set forth in full.

FIELD OF THE INVENTION

The field of this invention relates to devices and methods for quieting systems such as compressor systems, which generate pressure pulses and vacuum pulses during operation.

BACKGROUND OF THE INVENTION

Portable oxygen concentrators are commonly used in the home medical market to treat ambulatory patients with chronic obstructive pulmonary diseases. To make an oxygen concentrator portable, the oxygen concentrator must be as small as possible and weigh as little as possible while delivering sufficient concentrated oxygen gas flow to the ambulatory patient. Because a portable oxygen concentrator is used in a variety of different environments where low noise levels are important (e.g., restaurants, places or worship, libraries), it is important for the portable oxygen concentrator to be quiet during operation.

Air compressors are used in oxygen concentrators to supply high-pressure feed air to a Pressure Swing Adsorption (PSA) Module or concentrator. Air compressors, especially combined compressor and vacuum pumps, are relatively noisy during operation because pressure and vacuum pulses are generated simultaneously during operation, and these pressure and vacuum pulses generate noise.

SUMMARY OF THE INVENTION

To solve these problems and others, an aspect of present invention involves a compact muffler that reduces sound without the flow losses of tortuous path mufflers or the large size of Helmholtz resonators. The compact muffler is used in devices where a pulsating exhaust stream and a pulsating intake stream, which are at similar pressures, both need to be muffled. The compact muffler includes two chambers separated by a diaphragm wherein vacuum pulses from one stream may be canceled against pressure pulses in another stream by means of the diaphragm which allows pressure and volume to be exchanged between each stream, while not allowing the streams to intermix.

A further aspect of the invention involves a diaphragm muffler for quiet operation of a compressor, the compressor imparting an above atmospheric pressure stream and a below atmospheric pressure stream. The diaphragm muffler including a diaphragm pressure chamber receiving the above atmospheric pressure stream; a diaphragm vacuum chamber receiving the below atmospheric pressure stream; and a flexible diaphragm dividing the diaphragm pressure chamber receiving the above atmospheric pressure stream from the diaphragm vacuum chamber receiving the below atmospheric pressure stream, whereby the above atmospheric pressure stream and the below atmospheric pressure stream cancel each other out via the flexible diaphragm.

Another aspect of the invention involves a method of using a diaphragm muffler. The method includes receiving above atmospheric pressure stream in the diaphragm pressure chamber of the diaphragm muffler described immediately above; receiving below atmospheric pressure stream in the diaphragm vacuum chamber; and using the flexible diaphragm for canceling out the above atmospheric pressure stream and the below atmospheric pressure stream without mixing the above atmospheric pressure stream and the below atmospheric pressure stream.

Further objects and advantages will be apparent to those skilled in the art after a review of the drawings and the detailed description of the preferred embodiments set forth below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simple schematic of an embodiment of a gas separation device, which is an exemplary system/environment for the diaphragm muffler.

FIG. 2 is an cross-sectional view of a diaphragm muffler constructed in accordance with an embodiment of the invention.

FIG. 3A is perspective view of an embodiment of compressor system with portions of a housing removed, and illustrates another embodiment of diaphragm muffler.

FIG. 3B is another perspective view of an embodiment of compressor system with portions of a housing removed, similar to FIG. 3A.

FIG. 4 is perspective view of the compressor system of FIG. 3 with substantially the entire housing shown, and illustrates an external view of the diaphragm muffler.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

With reference to FIG. 1, a gas separation device 10 constructed in accordance with an embodiment of the invention will first be described before describing an embodiment of a diaphragm muffler 100. The gas separation device 10 may include a compressor 20 (e.g., rotary piston air compressor, diaphragm-type air compressor), which may be combination compressor/vacuum generator (hereinafter “compressor”), a Pressure Swing Adsorption (PSA) Module or concentrator 30, a measurement mechanism 40, and a flow control mechanism 50.

In a preferred embodiment, the gas separation device 10 is a portable oxygen concentrator weighing in the range of 2-20 pounds. An example portable oxygen concentrator system that comprises the gas separation device 10 is shown and described in U.S. Pat. No. 6,691,702, which is hereby incorporated by reference herein as though set forth in full. In particular, the portable oxygen concentrator system 100 and described with reference to FIGS. 1-16, and especially FIGS. 1, 2, 12, 15, and 16, may be used as the gas separation device 10.

In use, a feed fluid such as ambient air may be drawn into the compressor 20 and delivered under high pressure to the PSA Module 30. In a preferred embodiment, the compressor 20 is a combination compressor and vacuum pump/generator. The vacuum generator is preferably driven by the same motor as the compressor and is integrated with the compressor. The vacuum generator draws exhaust gas from the PSA module 30 to improve the recovery and productivity of the PSA module 30. The PSA module 30 separates a desired product fluid (e.g., oxygen) from the feed fluid (e.g., air) and expels exhaust fluid. Characteristics of the product fluid (e.g., flow/purity) may be measured by a measurement mechanism 40. Delivery of the product fluid may be controlled with the flow control mechanism 50.

With reference to FIG. 2, an embodiment of a diaphragm muffler 100 for use with the compressor 20 will be described. The diaphragm muffler 100 includes a diaphragm housing 110, which has curved surfaces to resist flexure due to internal pressure fluctuations and an internal surface that may be lined with sound attenuating material, a pressure inlet 120 and a pressure outlet 130 to conduct pressure fluctuations from the outlet of the compressor 20, a diaphragm pressure chamber 140 communicating with the pressure inlet 120 and the pressure outlet 130, a vacuum inlet 150 and a vacuum outlet 160 to conduct vacuum fluctuations from the inlet of the compressor 20, a diaphragm vacuum chamber 170 communicating with the vacuum inlet 150 and the vacuum outlet 160, and a diaphragm 180. The diaphragm muffler volume is substantially the same volume as the compressor volume, about 10 cc for a 30 liter/minute compressor. In a preferred embodiment, the diaphragm muffler volume is less than 30 cc. In a more preferred embodiment, diaphragm muffler volume is less than 20 cc. In a most preferred embodiment, diaphragm muffler volume is less than 15 cc. The diaphragm 180 physically separates the pressure gases and the vacuum gases, and allows the pressure fluctuations from a high pressure portion of the compressor 20 to cancel out the pressure fluctuations from the vacuum portion of the compressor 20. The diaphragm material should be flexible and thin, so that it reacts to pressure fluctuations in the air and it should be long lasting. Silicone rubber, approximately 1 mm thick is ideal. An interior wall surface of diaphragm housing 110 and opposite sides of diaphragm 180 define the diaphragm pressure chamber 140 and the diaphragm vacuum chamber 170.

Conduits (not shown) to and from the compressor 20 are configured to have lengths and diameters that create appropriate delays so that the pressure and vacuum pulsations cancel out in the diaphragm muffler 100 to the greatest possible degree. Preferably the inlet and outlet conduits are directed toward the diaphragm 180 to maximize the movement of the diaphragm and thereby the attenuation of the pulsations.

The diaphragm muffler 100 will now be described in use. During operation of the compressor 20 (combination compressor/vacuum generator), the vacuum generator draws exhaust gas (exhaust stream) from the PSA module 30 in pulses. This pulsating exhaust stream below atmospheric pressure enters the diaphragm vacuum chamber 170 via the vacuum inlet 150 and exits the diaphragm vacuum chamber 170 via the vacuum outlet 160. Simultaneously, feed fluid (intake stream) under high pressure is delivered in pulses by the compressor 20 to the PSA module 30. This pulsating pressure stream above atmospheric pressure enters the diaphragm pressure chamber 140 via the pressure inlet 120 and exits the diaphragm pressure chamber 140 via the pressure outlet 130. Pressure fluctuations through the diaphragm pressure chamber 140 cancel out pressure fluctuations through the diaphragm vacuum chamber 170 via the diaphragm 180, which physically separates the pressure gases and the vacuum gases. Thus, in the diaphragm muffler 100, to enable quieter operation of the compressor 20, the pulsating exhaust stream and the pulsating intake stream, which are at similar pressures, cancel each other out via without mixing the streams via the diaphragm.

FIGS. 3A, 3B, and 4 are perspective views of an embodiment of compressor system 200 including a combination compressor/vacuum generator (hereinafter “compressor”) 220, and a compressor system housing 230. The compressor system housing 230 includes a diaphragm muffler 300 similar to the diaphragm muffler 100 describe above with respect to FIG. 2. The diaphragm muffler 300 includes a diaphragm housing 310 that is integral with the compressor system housing 230, a pressure inlet 320 and a pressure outlet 330 to conduct pressure fluctuations from the outlet of the compressor 220, a diaphragm pressure chamber 340 communicating with the pressure inlet 320 and the pressure outlet 330, a vacuum inlet 350 and a vacuum outlet 360 to conduct vacuum fluctuations from the outlet of the vacuum pump of compressor 20, a diaphragm vacuum chamber 370 communicating with the vacuum inlet 350 and the vacuum outlet 360, and a diaphragm 380. The diaphragm muffler 300 is used in a similar manner as the diaphragm muffler 100 described above, and, therefore, the use of the diaphragm muffler 300 will not be described in further detail.

Accordingly, the diaphragm muffler 100, 300 is a compact muffler that reduces sound by having the pulsating exhaust stream and the pulsating intake stream, which are at similar pressures, cancel each other out without mixing the streams.

The above figures may depict exemplary configurations for the invention, which is done to aid in understanding the features and functionality that can be included in the invention. The invention is not restricted to the illustrated architectures or configurations, but can be implemented using a variety of alternative architectures and configurations. Additionally, although the invention is described above in terms of various exemplary embodiments and implementations, it should be understood that the various features and functionality described in one or more of the individual embodiments with which they are described, but instead can be applied, alone or in some combination, to one or more of the other embodiments of the invention, whether or not such embodiments are described and whether or not such features are presented as being a part of a described embodiment. Thus the breadth and scope of the present invention, especially in the following claims, should not be limited by any of the above-described exemplary embodiments.

Terms and phrases used in this document, and variations thereof, unless otherwise expressly stated, should be construed as open ended as opposed to limiting. As examples of the foregoing: the term “including” should be read as mean “including, without limitation” or the like; the term “example” is used to provide exemplary instances of the item in discussion, not an exhaustive or limiting list thereof; and adjectives such as “conventional,” “traditional,” “standard,” “known” and terms of similar meaning should not be construed as limiting the item described to a given time period or to an item available as of a given time, but instead should be read to encompass conventional, traditional, normal, or standard technologies that may be available or known now or at any time in the future. Likewise, a group of items linked with the conjunction “and” should not be read as requiring that each and every one of those items be present in the grouping, but rather should be read as “and/or” unless expressly stated otherwise. Similarly, a group of items linked with the conjunction “or” should not be read as requiring mutual exclusivity among that group, but rather should also be read as “and/or” unless expressly stated otherwise. Furthermore, although item, elements or components of the disclosure may be described or claimed in the singular, the plural is contemplated to be within the scope thereof unless limitation to the singular is explicitly stated. The presence of broadening words and phrases such as “one or more,” “at least,” “but not limited to” or other like phrases in some instances shall not be read to mean that the narrower case is intended or required in instances where such broadening phrases may be absent. 

1. A diaphragm muffler for quiet operation of a compressor, the compressor imparting an above atmospheric pressure pulsation stream and a below atmospheric pressure stream, comprising: a diaphragm pressure chamber receiving the above atmospheric pressure pulsation stream; a diaphragm vacuum chamber receiving the below atmospheric pressure pulsation stream; a flexible diaphragm dividing the diaphragm pressure chamber receiving the above atmospheric pressure pulsation stream from the diaphragm vacuum chamber receiving the below atmospheric pressure stream, whereby the above atmospheric pressure pulsation stream and the below atmospheric pressure stream cancel each other out via the flexible diaphragm.
 2. The diaphragm muffler of claim 1, wherein the compressor is a combination compressor/vacuum generator.
 3. The diaphragm muffler of claim 2, wherein the compressor is part of a pressure swing adsorption concentrator.
 4. The diaphragm muffler of claim 3, wherein the pressure swing adsorption concentrator is a portable oxygen concentrator including a Pressure Swing Adsorption (PSA) module, the below atmospheric pressure stream is a pulsating exhaust stream drawn from the PSA module by the combination compressor/vacuum generator and the above atmospheric pressure stream is a pulsating intake stream delivered under high pressure to the PSA module by the combination compressor/vacuum generator.
 5. The diaphragm muffler of claim 1, wherein the diaphragm muffler includes a pressure inlet and a pressure outlet in communication with the diaphragm pressure chamber, and a vacuum inlet and a vacuum outlet in communication with the diaphragm vacuum chamber, wherein the above atmospheric pressure pulsation stream enters the diaphragm pressure chamber through the pressure inlet and exits the diaphragm pressure chamber through the pressure outlet, and the below atmospheric pressure stream enters the diaphragm vacuum chamber through the vacuum inlet and exits the diaphragm vacuum chamber through the vacuum outlet.
 6. A method of using a diaphragm muffler, comprising: providing the diaphragm muffler of claim 1; receiving above atmospheric pressure pulsation stream in the diaphragm pressure chamber; receiving below atmospheric pressure pulsation stream in the diaphragm vacuum chamber; using the flexible diaphragm for canceling out the above atmospheric pressure stream and the below atmospheric pressure stream without mixing the above atmospheric pressure stream and the below atmospheric pressure stream.
 7. The method of claim 6, wherein the compressor is a combination compressor/vacuum generator and is part of a portable oxygen concentrator including a Pressure Swing Adsorption (PSA) module, the below atmospheric pressure stream is a pulsating exhaust stream drawn from the PSA module by the combination compressor/vacuum generator and the above atmospheric pressure stream is a pulsating intake stream delivered under high pressure to the PSA module by the combination compressor/vacuum generator. 